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Bioytite os fs sccoo ltnea]]
UTC)
As mentioned in the headlining message on the page, someone needs to insert inline citations
And can we get ride of the 3rd citation? Thats a CHILD website... with no credentials to boast. I would like to see more appropriate citations from Encyclopaedia Britanica etc. 74.222.64.182 ( talk) 03:03, 15 September 2008 (UTC)
How did this difference come to be. True difference or different samples or methods?
I have what I believe to be generic biotite. My specific gravity measurement using water at 1 ATM and 20C gave pretty much exactly 3.33. I am not geologist, but do have a lab with very exact balances. My number is correct. How flexible are these numbers to define biotite? — Preceding unsigned comment added by 79.102.30.85 ( talk) 06:58, 31 August 2015 (UTC)
Reply: Specific gravity and density are different. Density is the mass per volume, and specific gravity is the density of a sample relative to a reference sample. If the question is about the range of reported density and specific gravity measurements, it is due to the chemical heterogeneity of natural samples. Biotite is a solid solution with aluminium, iron, and magnesium end members. — Preceding unsigned comment added by 129.11.86.22 ( talk) 09:27, 2 September 2015 (UTC)
Reply: as near as I can tell, density and specific gravity should be the same in this case. The reference material for specific gravity is presumably water at ~20C? I think there is some essential info missing to explain this difference, such as compositional differences between specimens used to quantify the range of values for biotite. — Preceding unsigned comment added by 37.196.59.76 ( talk) 07:53, 7 December 2015 (UTC)
I recently reverted a change to this article by an editor who used the edit summary "Biotite is NOT a mineral!". On further investigation it's clear that the editor was basically correct. However, it has proved difficult to find a term that is used commonly in the literature to describe this situation. I have opted to use "Biotite group" as that has been used (and definitely more that "Biotite series" or "Biotite sub-group", which were the main alternatives). Also, it seems clear from scanning through recent literature that most geologists (as opposed to mineralogists) are still happily using "biotite" as if it were a valid mineral species. I've made a start at reworking the article, but I'm a little unsure about how far to go, given that the current usage is to some extent at odds with the "official" mineralogical position. Mikenorton ( talk) 11:51, 29 August 2019 (UTC)
I reverted the addition of this paper to the article, because it was added by the first author. It's newly published, but looks interesting and relevant. I would appreciate comments from other editors on whether it should be included. Mikenorton ( talk) 11:39, 12 March 2021 (UTC)